The present invention relates to textile winding machines and more particularly to winding machines for producing cross-wound packages for subsequent use of the packages in pairs in simultaneously twisting and doubling yarn during which twisting and doubling the length of yarn drawn from one package of a pair is different from the length of yarn drawn from the other package of the pair.
It is known that yarns being doubled from different packages in machines such as two-for-one twisters do not behave identically. In most arrangements of this type, the packages are arranged vertically with one package creeled above the other, with the yarn drawn from the lower package being subjected to a greater tension than the yarn drawn from the upper package with the result that more yarn is drawn from the upper package than from the lower package. When both packages have the same length of yarn wound thereon the upper package will be depleted before the lower package with a residue of yarn remaining on the lower package that creates a problem in reusing or is a waste if discarded. This situation is especially disadvantageous when processing yarns having significant elasticity. Wool yarn is an example of a yarn that is notably subject to this disadvantage.
Winding systems have been developed to produce packages with different lengths of yarn on the same winding machine so that the different length packages can be subsequently used in simultaneous twisting and doubling with the upper package having the lesser yarn. These systems operate with some of the winding stations controlled to produce packages having less yarn wound thereon than at other winding stations. To accomplish this the winding stations can be controlled to wind different lengths of yarn at different time intervals or, e.g., half of the winding stations can be controlled to produce packages with more yarn thereon and the other half controlled for winding less yarn thereon. This is disclosed in Italian patent document 60456 B/79.
However, these known systems involve disadvantages in that the length of yarn wound at different winding stations may vary and, although the variation may not be great, continual yarn waste will result in the twisting and doubling operation.
Another disadvantage of the known systems is that of handling the yarn packages automatically so that when they come from different winding stations or from different halves of the winding machine, they will be discharged from the winding machine or presented for assembly in the subsequent processing in proper pairs of longer and shorter yarn length packages.